Thin sanitary paper roll method of manufacturing the paper roll, and thin sanitary paper for thin sanitary paper roll

Abstract

Disclosed is a sanitary tissue paper roll wherein, when a sanitary tissue paper roll of two-ply or three-ply is laid on a horizontal surface with its central axis in a horizontal orientation, and a circular plate indenter, having an area of 2 cm 2 and being arranged at a center of an upper surface of an outer periphery of a body of the roll, is vertically pressed at least at respective pressing pressures of 0.5 gf/cm 2 and 50 gf/cm 2 , a difference in depths upon this respective pressing is within a range of 2.5–3.5 mm. Also disclosed is a sanitary tissue paper roll made by winding one sheet or two layered sheets of sanitary tissue papers wherein a roll compressibility of the roll is 0.68–0.74 m/cm 2 , with the roll compressibility being defined as a value obtained by dividing a roll length by a cross section of the roll. Also disclosed is a sanitary tissue paper for a sanitary tissue paper roll, wherein a sample paper is compressed between steel plates, which respectively have a circular surface with a compression area of 2 cm 2 , at a maximum compression load of 50 gf/cm 2 , and upon returning of this paper sample, a linearity of a displacement curve between a load and a thickness is 0.2500–0.3300 for a one-ply, and 0.3400–0.3700 for a two-ply; and a thickness upon a load of 50 gf/cm 2 is equal to at least 0.1400 mm for a one-ply, and equal to at least 0.2500 mm for a two-ply.

1. A sanitary tissue paper for a sanitary tissue paper roll, comprising:
 one of a one-ply paper and a two-ply paper, 
 wherein said one-ply paper has characteristics such that
 (i) upon subjecting a sample of said one-ply paper to a compression load of at most 50 gf/cm 2  between circular compression surfaces of steel plates, with each of the circular compression surfaces having an area of 2 cm 2 , and then relieving the sample of the compression load so as to allow the sample to return to an original condition, a linearity of a displacement curve between the compression load and a thickness of the sample is 0.25–0.33, and 
 (ii) while subjecting the sample of said one-ply paper to a compression load of 50 gf/cm 2  between the circular compression surfaces, a thickness of the sample is at least 0.14 mm, and 
 
 wherein said two-ply paper has characteristics such that
 (i) upon subjecting a sample of said two-ply paper to a compression load of at most 50 gf/cm 2  between circular compression surfaces of steel plates, with each of the circular compression surfaces having an area of 2 cm 2 , and then relieving the sample of the compression load so as to allow the sample to return to an original condition, a linearity of a displacement curve between the compression load and a thickness of the sample is 0.34–0.37, and 
 (ii) while subjecting the sample of said two-ply paper to a compression load of 50 gf/cm 2  between the circular compression surfaces, a thickness of the sample is at least 0.25 mm. 
 
 
     
     
       2. The sanitary tissue paper according to  claim 1 , wherein
 said one-ply paper has characteristics such that
 (i) while a sample of said one-ply paper is subjected to a compression load of 0.5 gf/cm 2  between the circular compression surfaces the sample has a first thickness, and while the sample of said one-ply paper is subjected to a compression load of 50 gf/cm 2  between the circular compression surfaces the sample has a second thickness, with a difference between the first thickness and the second thickness being at least 0.20 mm, and 
 (ii) an amount of work upon compression of the sample of said one-ply paper between the circular compression surfaces is at most 0.2000 gf·cm/cm 2 , and 
 
 said two-ply paper has characteristics such that
 (i) while a sample of said two-ply paper is subjected to a compression load of 0.5 gf/cm 2  between the circular compression surfaces the sample has a first thickness, and while the sample of said two-ply paper is subjected to a compression load of 50 gf/cm 2  between the circular compression surfaces the sample has a second thickness, with a difference between the first thickness and the second thickness being at least 0.20 mm, and 
 (ii) an amount of work upon compression of the sample of said two-ply paper between the circular compression surfaces is at most 0.22 gf·cm/cm 2 . 
 
 
     
     
       3. The sanitary tissue paper according to  claim 2 , wherein
 said one-ply paper has characteristics such that when a sample of said one-ply paper having a width of 20 cm is
 (i) chucked at a chuck a chuck distance of 1 cm, then 
 (ii) bent forward up to a maximum curvature of 2.5 cm −1  through pure bending by maintaining one side of the sample in the shape of an arc, then 
 (iii) bent back to an original position, then 
 (iv) bent backward at a maximum curvature of −2.5 cm −1 , and then 
 (v) returned to the original position, 
 a relationship between curvature and a flexural moment exhibited by the sample demonstrates
 (1) said one-ply paper to have an average bending resistance in longitudinal and lateral directions of at most 0.008 gf·cm 2 /cm, with the bending resistance being expressed as an average inclination between a curvature of 0.5–1.5 cm −1 , and 
 (2) said one-ply paper to have an average flexural recoverability in the longitudinal and lateral directions of 0.003–0.005 gf·cm/cm, with the flexural recoverability being expressed as an average hysteresis width of a flexural moment between a curavature of 0.5–1.5 cm −1 , and 
 
 
 said two-ply paper has characteristics such that when a sample of said two-ply paper having a width of 20 cm is
 (i) chucked at a chuck a chuck distance of 1 cm, then 
 (ii) bent forward up to a maximum curvature of 2.5 cm −1  through pure bending by maintaining one side of the sample in the shape of an arc, then 
 (iii) bent back to an original position, then 
 (iv) bent backward at a maximum curvature of −2.5 cm −1 , and then 
 (v) returned to the original position, 
 a relationship between curvature and a flexural moment exhibited by the sample demonstrates
 (1) said two-ply paper to have an average bending resistance in longitudinal and lateral directions of at most 0.018 gf·cm 2 /cm, with the bending resistance being expressed as an average inclination between a curvature of 0.5–1.5 cm −1 , and 
 (2) said two-ply paper to have an average flexural recoverability in the longitudinal and lateral directions of 0.013–0.017 gf·cm/cm, with the flexural recoverability being expressed as an average hysteresis width of a flexural moment between a curavature of 0.5–1.5 cm −1 . 
 
 
 
     
     
       4. The sanitary tissue paper according to  claim 3 , wherein
 said one-ply paper has characteristics such that
 (i) an average value between an average friction coefficient of said one-ply paper for longitudinal and lateral directions on a front side of said one-ply paper and an average value between an average friction coefficient of said one-ply paper for longitudinal and lateral directions on a back side of said one-ply paper is 0.260–0.280, and 
 (ii) an average value between an average deviation of a friction coefficient for longitudinal and lateral directions on the front side of said one-ply paper and an average deviation of a friction coefficient for longitudinal and lateral directions on the back side of said one-ply paper is at most 0.032, 
 with the friction coefficient for the longitudinal and lateral directions on the front side being obtained by
 (i) contacting a friction piece, made from a piano wire, having a diameter of 0.5 mm and length of 5 mm with a front side of a sample of said one-ply paper along the length of the friction piece at a contact pressure of 10 gf, and then 
 (ii) moving the friction piece at a speed of 0.1 cm/second in a direction orthogonal to a length direction of the friction piece while a tension of 20 gf/cm is applied to the sample in a moving direction of the friction piece, and 
 
 with the average deviation of the friction coefficient for the longitudinal and lateral directions on the back side being obtained by
 (i) contacting the friction piece with a back side of the sample of said one-ply paper along the length of the friction piece at a contact pressure of 10 gf, and then 
 (ii) moving the friction piece at a speed of 0.1 cm/second in a direction orthogonal to a length direction of the friction piece while a tension of 20 gf/cm is applied to the sample in a moving direction of the friction piece, and 
 
 
 said two-ply paper has characteristics such that
 (i) an average value between an average friction coefficient of said two-ply paper for longitudinal and lateral directions on a front side of said two-ply paper and an average value between an average friction coefficient of said two-ply paper for longitudinal and lateral directions on a back side of said two-ply paper is 0.350–0.380, and 
 (ii) an average value between an average deviation of a friction coefficient for longitudinal and lateral directions on the front side of said two-ply paper and an average deviation of a friction coefficient for longitudinal and lateral directions on the back side of said two-ply paper is at most 0.029, 
 with the friction coefficient for the longitudinal and lateral directions on the front side being obtained by
 (i) contacting a friction piece, made from a piano wire, having a diameter of 0.5 mm and length of 5 mm with a front side of a sample of said two-ply paper along the length of the friction piece at a contact pressure of 10 gf, and then 
 (ii) moving the friction piece at a speed of 0.1 cm/second in a direction orthogonal to a length direction of the friction piece while a tension of 20 gf/cm is applied to the sample in a moving direction of the friction piece, and 
 
 with the average deviation of the friction coefficient for the longitudinal and lateral directions on the back side being obtained by
 (i) contacting the friction piece with a back side of the sample of said two-ply paper along the length of the friction piece at a contact pressure of 10 gf, and then 
 (ii) moving the friction piece at a speed of 0.1 cm/second in a direction orthogonal to a length direction of the friction piece while a tension of 20 gf/cm is applied to the sample in a moving direction of the friction piece. 
 
 
 
     
     
       5. The sanitary tissue paper according to  claim 4 , wherein
 said one-ply paper and said two-ply paper each have
 (i) grammage of 15–25 g/m 2 , 
 (ii) a thickness of 120–180 μm, 
 (iii) a longitudinal/lateral ratio of tension of 2.0–3.0, 
 (iv) an elongation rate in a longitudinal direction of 20–35%, 
 (v) a longitudinal tensile strength of 110–115 N/m, and 
 (vi) 30–50 crepes per cm. 
 
 
     
     
       6. A sanitary tissue paper roll comprising a roll of the two-ply paper according to  claim 4 , wherein 
       said roll, and a difference in depths resulting from pressing at the respective pressing pressures is continuously measured nine times, a difference between a maximum and a minimum of these nine differences in depth is within a range of 0.5–1.0 mm. 
     
     
       7. The sanitary tissue paper roll according to  claim 6 , wherein
 said roll of the two-ply paper has characteristics such that when a difference in depths resulting from pressing at the respective pressures is continuously measured nine times, each of these nine differences in depth is within the range of 2.5–3.5 mm, and a difference between a maximum and a minimum of these nine differences in depth is within a range of 0.5–1.0 mm. 
 
     
     
       8. A sanitary tissue paper roll comprising a roll of the one-ply paper according to  claim 4 , wherein
 said roll of the one-ply paper has characteristics such that when said roll is on a horizontal surface, with a central axis of said roll horizontally oriented, and a circular plate indenter having an area of 2 cm 2  is vertically pressed, at least at respective pressing pressures of 0.5 gf/cm 2  and 50 gf/cm 2 , against a central portion of an upper surface of an outer periphery of said roll, a difference in depths resulting from pressing at the respective pressing pressures is within a range of 1.5–2.5 mm. 
 
     
     
       9. A sanitary tissue paper roll comprising a roll of the sanitary tissue paper according to  claim 4 , wherein
 said roll of the sanitary tissue paper has characteristics such that when said roll is on a horizontal surface, with a central axis of said roll horizontally oriented, and a circular plate indenter having an area of 2 cm 2  is vertically pressed, at least at respective pressing pressures of 0.5 gf/cm 2  and 50 gf/cm 2 , against a central portion of an upper surface of an outer periphery of 
 with each of said sheets having a grammage of 15–25 g/m 2 , a density of 0.10–0.15 g/cm 3 , and a thickness of 20–170 μm. 
 
     
     
       10. A sanitary tissue paper roll comprising a roll of the sanitary tissue paper according to  claim 4 , wherein
 an elongation rate said sanitary tissue paper in a longitudinal direction of said sanitary tissue paper is 20–35%. 
 
     
     
       11. A sanitary tissue paper roll comprising a roll of the sanitary tissue paper according to  claim 4 , wherein
 said roll is formed by winding said sanitary tissue paper such that a roll compressibility of said roll is 0.68–0.74 m/cm 2 , with said roll compressibility being defined as a value obtained by dividing a length of said roll by a cross section of said roll. 
 
     
     
       12. The sanitary tissue paper roll according to  claim 11 , wherein said roll of the sanitary tissue paper comprises wound sheets of said sanitary tissue paper,
 with said sanitary tissue paper having characteristics such that a dry-state tensile strength, which is measured according to a tensile-characteristic testing method defined by JISP8113, for each of said sheets is at least 40 N/m in a width direction, and is 1–4 folds of the width direction in a longitudinal direction. 
 
     
     
       13. The sanitary tissue paper roll according to  claim 11 , wherein
 a number of crepes per cm of said sanitary tissue paper is 25–45 per cm, and an elongation rate of said sanitary tissue paper in a longitudinal direction is 15–25%. 
 
     
     
       14. The sanitary tissue paper roll according to  claim 11 , wherein said roll of the sanitary tissue paper comprises wound sheets of said sanitary tissue paper,
 said roll of the two-ply paper has characteristics such that when said roll is on a horizontal surface, with a central axis of said roll horizontally oriented, and a circular plate indenter having an area of 2 cm 2  is vertically pressed, at least at respective pressing pressures of 0.5 gf/cm 2  and 50 gf/cm 2 , against a central portion of an upper surface of an outer periphery of said roll, a difference in depths resulting from pressing at the respective pressing pressures is within a range of 2.5–3.5 mm. 
 
     
     
       15. The sanitary tissue paper roll according to  claim 11 , wherein
 said sanitary tissue paper comprises a paper made mainly of Nadelholz bleached kraft pulp and Laubholz bleached kraft pulp and having a weight proportion of Nadelholz bleached kraft pulp to Laubholz bleached kraft pulp of 10:90–70:30. 
 
     
     
       16. The sanitary tissue paper roll according to  claim 11 , wherein
 said sanitary tissue paper is embossed prior to winding said sanitary tissue paper to form said roll. 
 
     
     
       17. The sanitary tissue paper roll according to  claim 11 , wherein
 when said roll is formed by winding said one-ply paper, a roll length is 58–65 m, and 
 when said roll is formed by winding said two-ply paper, a roll length is 29–33 m. 
 
     
     
       18. The sanitary tissue paper roll according to  claim 11 , wherein
 said roll is formed made by winding said sanitary tissue paper around a core having an outer diameter of 30–40 mm. 
 
     
     
       19. A sanitary tissue paper for a sanitary tissue paper roll, comprising:
 one of a one-ply paper and a two-ply paper, 
 wherein said one-ply paper has characteristics such that when a sample of said one-ply paper having a width of 20 cm is
 (i) chucked at a chuck a chuck distance of 1 cm, then 
 (ii) bent forward up to a maximum curvature of 2.5 cm −1  through pure bending by maintaining one side of the sample in the shape of an arc, then 
 (iii) bent back to an original position, then 
 (iv) bent backward at a maximum curvature of −2.5 cm −1 , and then 
 (v) returned to the original position, 
 a relationship between curvature and a flexural moment exhibited by the sample demonstrates
 (1) said one-ply paper to have an average bending resistance in longitudinal and lateral directions of at most 0.008 gf·cm 2 /cm, with the bending resistance being expressed as an average inclination between a curvature of 0.5–1.5 cm −1 , and 
 (2) said one-ply paper to have an average flexural recoverability in the longitudinal and lateral directions of 0.003–0.005 gf·cm/cm, with the flexural recoverability being expressed as an average hysteresis width of a flexural moment between a curavature of 0.5–1.5 cm −1 , and 
 
 
 wherein said two-ply paper has characteristics such that when a sample of said two-ply paper having a width of 20 cm is
 (i) chucked at a chuck a chuck distance of 1 cm, then 
 (ii) bent forward up to a maximum curvature of 2.5 cm −1  through pure bending by maintaining one side of the sample in the shape of an arc, then 
 (iii) bent back to an original position, then 
 (iv) bent backward at a maximum curvature of −2.5 cm −1 , and then 
 (v) returned to the original position, 
 a relationship between curvature and a flexural moment exhibited by the sample demonstrates
 (1) said two-ply paper to have an average bending resistance in longitudinal and lateral directions of at most 0.018 gf·cm 2 /cm, with the bending resistance being expressed as an average inclination between a curvature of 0.5–1.5 cm −1 , and 
 (2) said two-ply paper to have an average flexural recoverability in the longitudinal and lateral directions of 0.013–0.017 gf·cm/cm, with the flexural recoverability being expressed as an average hysteresis width of a flexural moment between a curavature of 0.5–1.5 cm −1 . 
 
 
 
     
     
       20. A sanitary tissue paper for a sanitary tissue paper roll, comprising:
 one of a one-ply paper and a two-ply paper, 
 wherein said one-ply paper has characteristics such that
 (i) an average value between an average friction coefficient of said one-ply paper for longitudinal and lateral directions on a front side of said one-ply paper and an average value between an average friction coefficient of said one-ply paper for longitudinal and lateral directions on a back side of said one-ply paper is 0.260–0.280, and 
 (ii) an average value between an average deviation of a friction coefficient for longitudinal and lateral directions on the front side of said one-ply paper and an average deviation of a friction coefficient for longitudinal and lateral directions on the back side of said one-ply paper is at most 0.032, 
 with the friction coefficient for the longitudinal and lateral directions on the front side being obtained by
 (i) contacting a friction piece, made from a piano wire, having a diameter of 0.5 mm and length of 5 mm with a front side of a sample of said one-ply paper along the length of the friction piece at a contact pressure of 10 gf, and then 
 (ii) moving the friction piece at a speed of 0.1 cm/second in a direction orthogonal to a length direction of the friction piece while a tension of 20 gf/cm is applied to the sample in a moving direction of the friction piece, and 
 
 with the average deviation of the friction coefficient for the longitudinal and lateral directions on the back side being obtained by
 (i) contacting the friction piece with a back side of the sample of said one-ply paper along the length of the friction piece at a contact pressure of 10 gf, and then 
 (ii) moving the friction piece at a speed of 0.1 cm/second in a direction orthogonal to a length direction of the friction piece while a tension of 20 gf/cm is applied to the sample in a moving direction of the friction piece, and 
 
 
 wherein said two-ply paper has characteristics such that
 (i) an average value between an average friction coefficient of said two-ply paper for longitudinal and lateral directions on a front side of said two-ply paper and an average value between an average friction coefficient of said two-ply paper for longitudinal and lateral directions on a back side of said two-ply paper is 0.350–0.380, and 
 (ii) an average value between an average deviation of a friction coefficient for longitudinal and lateral directions on the front side of said two-ply paper and an average deviation of a friction coefficient for longitudinal and lateral directions on the back side of said two-ply paper is at most 0.029, 
 with the friction coefficient for the longitudinal and lateral directions on the front side being obtained by
 (i) contacting a friction piece, made from a piano wire, having a diameter of 0.5 mm and length of 5 mm with a front side of a sample of said two-ply paper along the length of the friction piece at a contact pressure of 10 gf, and then 
 (ii) moving the friction piece at a speed of 0.1 cm/second in a direction orthogonal to a length direction of the friction piece while a tension of 20 gf/cm is applied to the sample in a moving direction of the friction piece, and 
 
 with the average deviation of the friction coefficient for the longitudinal and lateral directions on the back side being obtained by
 (i) contacting the friction piece with a back side of the sample of said two-ply paper along the length of the friction piece at a contact pressure of 10 gf, and then 
 (ii) moving the friction piece at a speed of 0.1 cm/second in a direction orthogonal to a length direction of the friction piece while a tension of 20 gf/cm is applied to the sample in a moving direction of the friction piece.